Our laboratory is continuing investigation of the structural-functional relationships of normal and abnormal human hemoglobins. During the next five years, we plan to focus on two main projects: MOLECULAR BASIS OF SICKLING: The aggregation of sickle hemoglobin will be studied in two ways: The viscosity of concentrated solutions of deoxygenated S will be measured anaerobically in a capillary viscometer. The equilibrium between soluble hemoglobin S and sickle hemoglobin gel will be measured following centrifugation. These techniques will be used to evaluate the interaction of S and non S hemoglobins and to determine the role of the asymmetrical hybrid (such as alpha 2 beta S beta A) in the formation of sicle polymer. The effect of ionic strength and CO2 on sickling will also be determined. These experiments should provide new information on the orientation of the hemoglobin S molecule within the sickle fibers. EVALUATION OF NEW HEMOGLOBIN VARIANTS: Structural and functional studies will be done on a limited number of hemoglobin variants. We hope to adapt isoelectric focusing on polyacrylamide gels to the analysis of globin subunits and cyanogen bromide fragments. Autoradiography will be used as an adjunct for the interpretation of peptide maps on thin layer plates. Variants with abnormal oxygen binding or decreased stability will be of particular interest. We plan to utilize certain functionally abnormal hemoglobins to examine the mechanism of auto-oxidation.